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@@ -94,7 +94,7 @@ has simply been esterified differently than ASA.\\
\label{fig:methyl-salicylate}
\end{figure}
Due to the similarity between the two molecules, ASA can be reacted to synthesize methyl salicylate~\cite{Hartel2009}.
Due to the similarity between the two molecules, ASA can be reacted to synthesize methyl salicylate~\cite{Hartel2009,nilered2017aspirin}.
The purpose of this experiment was to convert acetylsalicylic acid obtained from
commercial aspirin tablets into methyl salicylate through acid-catalyzed esterification
in methanol under reflux conditions.
@@ -173,6 +173,33 @@ The transformation encompasses two concurrent equilibrium-driven processes:
To drive the reaction toward the methyl salicylate product, a substantial stoichiometric excess of methanol was employed, utilizing Le Chatelier's principle to overcome the reversible nature of the esterification.
\subsection{Kinetic and Thermodynamic Analysis}
The transformation efficiency of the tandem hydrolysis--esterification is determined by the interplay between reaction rate and equilibrium position.
\subsubsection{Thermal Activation and Collision Theory}
The reflux duration is required to provide the activation energy ($E_{a}$) necessary for the nucleophilic attack on the sterically hindered aryl ester. According to the Arrhenius relationship, the rate constant $k$ increases exponentially with temperature:
\begin{equation}
k = Ae^{-E_{a}/RT}
\end{equation}
Operating at the boiling point of the solvent increases the frequency of effective collisions and facilitates the formation of the required carbocation intermediates.
Furthermore, by employing a vast molar excess of methanol, the system effectively follows pseudo-first-order kinetics. Under these conditions, the concentration of the alcohol remains negligible in its variation, and the rate depends solely on the concentration of the limiting aspirin precursor:
\begin{equation}
-\frac{d[\text{ASA}]}{dt} = k'[\text{ASA}] \implies [\text{ASA}]_{t} = [\text{ASA}]_{0}e^{-k't}
\end{equation}
\subsubsection{Equilibrium Shifts and Chemical Potential}
As a reversible process, the yield is limited by the equilibrium constant ($K$). Because the esterification step is endothermic ($\Delta H^\circ > 0$), the application of heat shifts the equilibrium toward the products. This temperature dependence is quantified by the Van't Hoff equation:
\begin{equation}
\frac{d \ln K}{dT} = \frac{\Delta H^\circ}{RT^{2}}
\end{equation}
The high reactant-to-substrate ratio further ensures that the reaction quotient ($Q$) remains lower than $K$ throughout the process. This maintains a negative Gibbs free energy ($\Delta G$), driving the reaction toward the formation of methyl salicylate:
\begin{equation}
\Delta G = \Delta G^\circ + RT \ln Q
\end{equation}
The combination of thermal input and stoichiometric bias effectively overcomes the reversible nature of the Fischer esterification.
\subsection{Work-up and Purification}
Following reflux, the reaction was quenched in ice-cold distilled water. Methyl salicylate ($\rho \approx 1.17$ g/mL) was isolated as the organic phase via liquid--liquid extraction. Residual acidic species (\ce{H2SO4}, \ce{CH3COOH}) were neutralized using saturated \ce{NaHCO3}:
@@ -183,113 +210,9 @@ Following reflux, the reaction was quenched in ice-cold distilled water. Methyl
The organic extract was dried over anhydrous \ce{MgSO4} and filtered to yield the pure essential oil.
\subsection{Outline}
The document layout should follow the style of the journal concerned. Where
appropriate, sections and subsections should be added in the normal way.
\subsection{References}
References should be given in the normal way in \LaTeX{}. If you are using
\textsf{biblatex} (as recommended) then you can use the full range of citation
commands it provides. If you choose to use classical Bib\TeX{}, the
\textsf{natbib} package will be loaded and you can use it's commands.
\subsection{Floats}
New float types are set up in the preamble. The means graphics are included as
follows (Scheme~\ref{sch:example}). As illustrated, the float is ``here'' if
possible.
\begin{scheme}
\centering
Your scheme graphic would go here: PDF graphics are recommended.
%\includegraphics{graphic}
\caption{An example scheme}
\label{sch:example}
\end{scheme}
The use of the different floating environments is not required, but it is
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\subsection{Math}
If packages such as \textsf{amsmath} are required, they should be loaded in the
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\begin{equation}
\frac{\mathrm{d}}{\mathrm{d}x} \, r^2 = 2r \label{eqn:example}
\end{equation}
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\begin{equation}
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the minipage needs to allow some \\
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%\includegraphics{graphic}
\end{minipage}
\label{eqn:graphic}
\end{equation}
\section{Experimental}
The usual experimental details should appear here. This could include a table,
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\begin{table}
\caption{An example table}
\label{tbl:example}
\centering
\begin{tabular}{ll}
\hline
Header one & Header two \\
\hline
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Entry three & Entry four \\
Entry five & Entry five \\
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\hline
\end{tabular}
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\caption{A table with notes}
\label{tbl:notes}
\centering
\begin{tabular}{ll}
\hline
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\hline
Entry one\textsuperscript{\emph{a}} & Entry two \\
Entry three\textsuperscript{\emph{b}} & Entry four \\
\hline
\end{tabular}
\textsuperscript{\emph{a}} Some text;
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\end{table}
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\section*{Acknowledgements}

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@@ -55,3 +55,14 @@
month = Apr,
pages = {475}
}
@online{nilered2017aspirin,
author = {NileRed},
title = {Turning aspirin pills into mint flavor},
year = {2017},
month = jul,
day = {17},
organization = {YouTube},
url = {https://www.youtube.com/watch?v=3NN9IUvrKi4},
note = {YouTube video, 10.7M subscribers, 2,057,102 views, accessed 2026-05-12}
}